49. In a circuit consisting of an EMF source and a resistor with a resistance of R = 10 Ohms, a voltmeter is included, the resistance of which is RV = 500 Ohms, one time in series with the resistor, the other time in parallel. Determine the internal resistance of the source if the voltmeter readings are the same in both cases.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)